Electrical system and signaling method



Dec. 6 1927.

A. F. VAN DYCK ELECTR CAL SYSTEM AND SIGNALING METHOD Filed Way 27.1924- 2 Sheets-Sheet 1 Evweutoz ARTHUR F. VAN DYCK Patented Dec; 6, 1927. a

UNITED STATES ARTHUR F. VAN DYCK, OF RYE, NEW YOBK A SSI GNOR TO BAsDIOCORPORATION OF PATENT,

AMERICA, A CORPORATION or DELAWARE;

ELECTRICAL sirsrnlvr AND SIGNALING mnrnonj Application fi led May 27,

6 the autodyne method of producing beat o.s-.

'cilla'tions. t

certain radio receiving systems of the prior art successfully employingthe autodyne method of detecting and amplifying} 10 continuous signaloscillations, reliance has been .placed uponfthe use of some harmonic(-usually the second) of oscillations produced by the oscillating tubeat a fundamental frequency substantially ,lower than the frequenc of theincoming signal waves to produce some desired beat frequency. A con-.crete example of this is as followszSuppose the incoming signaloscillations possess. a frequency of 600 kilocycles and a beat fre-.

cillating tube is then arranged to oscillate at a fundamental frequencyof say 320 or 280 kilocycles, the second harmonic, 6&0 or

560 kilocycles of these fundamental fr'equen-- responding late currentvariations. Therefore, for a given amplitude'of the second harmonic,heavier loads are placed on the oscillating tube owing to the influenceof the fundamental than would exist if the fundamentalwere employed forproducing the beat oscillations. I 3

,The use of the so-called second harmonic also brings into the operatingrange of such a system a large number of combinations of V frequencieswhich are present when signal oscillations are received. The result isthat signals are received and detected at a multiplicity of adjustmentsof the oscillating tube iniilti piieity of adjustments naturally results1 quency of 40 kilocycles is desired, The osQ produce I grid of theoscillating tube resulting in corfrequency instead of at only twopositions 1924, Serial No. 716,146.

in great confusion to the operator when attempting to adjust the systemfor the detection of the desired signal oscillations; while simplicity vof adjustment naturally results from the employment of full frequency(560' kilocy'cles or 640 kilocycles in the concrete examplegiven above).v

Heretofore certain difliculties existed which precluded the successfulemployment of the so-called full frequency in certain autodyne receptionand detection systems. For example the oscillator grid circuit "andantenna circuit are necessarily tuned to substantially the samefrequency The ordinary manipulation of the controls oftenbrings theminto exact resonance with each other.

This condition will rob the grid of the oscillatin'g tube of the voltageswings of the incoming signal oscillations and in some cases will evenstop the oscillator from producing the desired'oscillations therebyresulting in the'non-det'ection of the incoming signal waves and theconsequent inoperativeness of the system. The energy'fr'om theoscillator will alsoin some cases appear in the antenna and beradiated-therefrom.

The means for coupling the first and second tubes and the means fortuning the grid of the second tube, whichisthe oscillator, are ofnecessity both in the grid circuit of the second tube and since both aretuned to substantially the same frequency they naturally influence eachother. Each acts as a trapor filter circuit for the other and preventsthe necessary transferof voltage from one to theother, as desired. Theresults of "this are lessened sensitivity of the system andeven,Qinoperativeness when incoming signal oscillations of certainfrequencies are received. j

H One of jtheprincipal objects of my invention is the employment of fullfrequency in autodyne systems for the reception and de tection(if-signal oscillations with all the resulting advantages of simplicityof "adjustment, decrease of the load on the oscillator tube and otheradvantages which will appear in the course of theodescription of myinvention.

, Another principal objectjof my -invention is to overcome the above'difiiculties in auto dynesystems in order that so-calledfull fre.quency oscillations maybe employed for combinin with the signaloscillations to (ill produce the required beat frequency for de tectionand amplification.

Other objects and advantages of my invention will be evident from thefollowing description taken in connection with the accompunyingdrawings, in which:

Fig. l is a schematic diagram of a radio receiving system of theautodyne and reflexing type and Fig. 2 is a schematic diagram of a radioreceiving system employing antodyne, neutralizing and reflexingprinciples for the reception and detection of incoming signaloscillations.

Referring to Fig. 1 the terminals of loop antenna are connected to thegrid and filament of a three-element thermionic device or tube 21 and avariable condenser 22 is connected across the terminals of the loopantenna for tuning the same to the incoming signal waves. The plate ofthermionic de vice 21, which functions as a radio frequency amplifier,connected to the grid of the combined oscillating and detectingthree-element thermionic device or tube 23 through a small. blockingcondenser 24' for preventing the impression of the B-battery voltage ofthe plate-filan'ient circuit of tube 21 on the grid element of tube 23.

An inductance coil 24; is connected across the grid and filament of tube23,11. variable tuning condenser 25 being connected in shunt with thecoil. The plate-filament circuit of tube 23 comprises its battery B theprimary winding 26 of intermediate frequency transformer 26 and atiolrler coil 27 nductively coupled to the inductance coil let, thebattery B With primary winding 26" of intermediate frequency transformer26 and the ticlrler coil 27 all being connected in. series. d

A condenser 28 is shunted across the primary Winding of transforn'ier 26for bypassing undesired high frequency oscillations and for tuning thetransformer to the desired beat frequency and a blocking condenser 29 isso connected in the lead connect ing one terminal of the loop antenna 20and the grid of tube 21 so as to prevent the intermediate frequencyoscillations being impressed on the loop antenna and atthe same time soconnected as to loosenthe capacitative coupling through tube 21 of thecircuit com rising inductance 2t and condenser 25 to tie circuitcomprising the loop 20 and condenser 22. a

The secondary winding 26 of heat frequency transformer 26 is connectedacross the grid and filament of tube 21. the connection to the grid oftube 21 being made between the grid and condenser 29. The plate filamentcircuit of tube 21 also com arises the 1: ri1nary winding 30 of heatrequency transformer 30 and the Bbattery 13 both connected in series,the connection to the plate of tube 21 not including the condenser 24'.The secondary winding BO of heat frequency transformer 30 is connectedacross the grid and filament of the three-element thermionic device oramplifying tube 31.

The platefilament circuitof amplifying tube 31 comprises the primaryWinding 32" of beat frequency transformer 32 and battery B bothconnected in series and the condenser ll shunting the primary Winding32" for properly tuning the plate-filament circuit to the desired beatfrequency and for preventing any undesired high frequency oscillationspassing through the primary winding 32" of the transformer.

The secondary winding 32 quency transformer 32 is connected in thegrid-filament of the three element detecting tube 33 and the usual gridcondenser 34 shunted by a grid leak 35 is also included in thegrid-filament circuit.

The audio frequency oscillations appearing in the plate-tilament circuitof detector tube 35} may be amplified by means of the audio frequencyamplifying three-element the grid of tube 21. Tube 21 amplifies thoseradio frequency oscillations which are in turn impressed onthc grid ofthe combined By means oscillating and detecting tube 23. of the ticklercoil 27 and a proper adjustment of the variable condenser 25 the tube 23is made to produce oscillations at a frequency equal to the frequency ofthe incoming signal oscillations minus or plus the desired beatfreqnencyoscillations. Owing to the fact that the inductance coil 24 and thevariable condenser 25 are connected across the grid and filament of thetube the incoming high frequency signal oscillations will be in' pressedonthe grid of tube 23 and no dimii'uition but in fact magnification ofpotential on thegrid will result even ifthe condenser is adjusted tomake the coup ling comprising induct auce 2land condenser 25 resonanttothe incomin signal oscillations.

The beat frequency oscillations appearing in the plate-filament circuitof tube 23 are now impressed on the grid and filament of tube 21 bymeans of the beat frequency of heat fire no tubes 36 and 37 and theaudio frequency transformer 26, the condenser 28 bypassing all theundesired high frequency oscillations and also serving to tune theplate-filament circmt oftube 23 to the desired beat frequency;oscilltions. K i

The beat frequency oscillations considerably amplified by tube 21 willnow lfiow tl1rou "gh the plate filament circuit of tube 21- in which is"included the primary winding, 30* of beat frequency transformer 30, the

secondary winding 30' of which impresses these beat frequencyoscillations on the grid' filament circuit of the beat frequencyamplifying tube 31. The amplified beat frequency current oscillationsflowing in the plate-filament circuit of tube 31 are then impressed onthe grid-filament circuit of the intermediate frequency detecting tube33.

The audio ,frequencyoscillations appearing -in theiplate-filamentcircuit of tube 33 are then further amplified by means of the audiofrequency amplifying tubes 36 and 37 and the sound reproductive device40 operates in response tothe amplified audio frequency Currents flowingthe plate-filament circuit of the last amplifying tube 37.

-"R'eferrin'g to the Fig. '2, a variable tuning condenser is connectedacross the terminals of the loop antenna 51; One terminal of the loopantenna 51 is connected to the fgrid of a three-element thermionicdevice or tube "52 through a blocking condenser 53 d and the otherterminal of the loop "antenna f comprisesfthe primary winding H vnequenc transformer 54 and-. pla'te battery isconnectedjto Ithe filamentof the tube 52. v 1 The plate-filament circuit of tube 52,"whichfunctions. as a radio frequency amplifier, 54 of beat B, both of whichare'connected in series with each other in .the said .plateefilamentcircuit. The plate of tube 52 is also connected to the grid of thecombined oscillating and detecting tube 55-throu 11 the condenser 56 notincluded in the main plate-filament circuit of tube 52. This'condenserprevents the impression of the B-battery voltage on the grid of tube'55.An inductance coil 57 is connected across the grid and filament of tube55 and a variable tuning condenser 58 is connected in shunt with theinductance coil.

The plate-filament circuit of tube 55 comprises a tickler coil 59inductively coupled to the inductance coil 57, the primary Winding 60 ofabeat frequency transformer 60 and" the plate battery B all of which are"frequency oscillations.

series; The secondary winding and for tuning the .plat'e "filamentcircuit bf t'hetube 55 for the intermediate of beat The capacity of'tube5'2 together with that of condenser 56 is balanced by means of a'lead, one extremity of which is connected 'to the grid of tube 52, in.which is connected a balancing condenser 162and anTinductance "coil. 63'inductively coupled '{to the induction coil 57, the other extremity ofthe lead being connected to the filament extremity of inductance coil57. The'coils '57 and 'ti V f are so arranged that the voltages thereinbalancing of'the capacity of tubef 52 isthus' accomplished therebypreventing any 'undesirable. reaction between the loop antenna and theoscillating tube circuits and preventiing radiation of oscillating tubeenergy from.

theloop antenna' 7 V p v The secondary winding 54 of boat frequencytransformer 5l is connected, across the grid a'ndfila'mentJdf theintermediate frequency amplifying tube '64, whose "pia telilameiitcircuit comprises the primary winding 65 of beat frequency transformer-65 "and plate'i battery B both being connected it} o transformer T65 isconnected across thegrid and filament of the audible frequency de-'te'ctortube 66having the usual grid condenser 67 and grid leak 68connected to the grid in the usualmann'era's shown.

.Tlie" audio frequency currents appearing in the platefilament circuit'ofthe. detector tube GG may 'bef f'urther amplified by means of t-heaudio frequency amplifying tubes 69 aiidTO suitably coupled by means ofthe audio frequency transformers 71 and 72.

supplied with heating currents from the common source of power A andindividual control of the currents in the various filaments may beeffected by means of the rheostats R. 7

This system functions in substantially the same way as the system shownin Fig. 1, the only difference being that thecapacity of the radiofrequency amplifier is balanced by means of the balancing condenser 62and the coupler coil 63, which acts as an additional safeguard againstthe existence of undesirable oscillations in the loop circuit andundesirable reactions between the loop and oscillator circuits. Theexplanation given above for the operation of the system as shown by Fig.1 is, therefore, thought to be suflicient as an explanation of themanner inwhich this embodiment of my. invention.

lit)

preferred modifications of my invention I wish it understood that I donot limit my self to said modifications but may employ many otherembodiments which come Within the spirit and scope of my invention.

Having described my invention, what I claim is: i

1, A superheterodyne receiving system comprising a tunable circuitadapted to have signaling currents set up therein, a vacuum tubeamplifier having its input cir' cuit connected to said tunable circuitand its output circuit coupled to a combined oscillator and detector bymeans of a common tunable circuit likewise serving to fix the frequencyof oscillation of the generator and condensers connected in series inthe amplifiercircuits to loosen the inhcrentcapacitative couplingthrough the amplifier tube to prevent absorption of energy from theoscil lator circuits by the first named tunable circuit.

2. A superheterodyne receiving system comprising a tunable circuitadapted to have signaling currents set up therein, a radio frequencyamplifier having its input circuit connected to said circuit with acondenser in series between said circuit and the amplifier, a combinedoscillator and detector connected to the output circuit of saidamplifier by means of a common impedance for impressing the output ofsaidiamplificr on the input of said detector and forfixing the frequencyof oscillation of said oscillator and a second condenser connectedbetween said amplifier and said impedance wherebythe coupling betweensaid impedance and said first named circuit will be loose enough toprevent absorption of energy by the latter from the former. y

3. A superheterodyne receiving system comprising a tunable circuitadapted to have signaling currents set up therein, a radio 'l'requencyamplifier coupled thereto, the com pling comprising acondenser in serieswith the lead from the grid of said amplifier to said tunable circuit,means for coupling said radio frequency amplifier to a combinedoscillator and detector, means for reflexing the output of said combineddetector and oscillater into said radio frequency amplifier,

said last named means comprising a. second ary coil. of a transformerconnected across the grid and filament of said amplifier wherebydetecting effects of the condenser in said grid circuit are eliminated.

4-. A superhetcrodyne receiving system pedance whereby the couplingbetween said impedance and said first named circuit will be loose enoughto prevent absorption ofenorgy by the latter from the former, means forretiexing the output of the combined oscillator and detector means intothe radio frequency amplifier, said means comprising a secondary coil ofa transformer connected between said first mentioned condenser and gridand to the filament of said radio frequency amplifier for preventingdetecting effects of said condenser.

Mar ana F. VAN DYCK.

